Inkjet head and inkjet printer

Abstract

In accordance with an embodiment, an inkjet head comprises a first actuator and a second actuator, a first electrode, a second electrode, a third electrode, and a drive controller. The first actuator and the second actuator constitute a pressure chamber. The first electrode comes in contact with the first actuator from the outer side of the pressure chamber. The second electrode comes in contact with the first actuator and the second actuator from the inner side of the pressure chamber. The third electrode comes in contact with the second actuator from the outer side of the pressure chamber. The drive control section outputs an auxiliary pulse which generates volume change in the pressure chamber that is smaller than volume change of the pressure chamber generated by an ejection pulse for ejecting ink from the pressure chamber to the first electrode, the second electrode, and the third electrode.

What is claimed is: 
     
         1 . An inkjet head, comprising:
 a first actuator and a second actuator configured to constitute a pressure chamber;   a first electrode configured to contact the first actuator from an outer side of the pressure chamber;   a second electrode configured to contact the first actuator and the second actuator from an inner side of the pressure chamber;   a third electrode configured to contact the second actuator from the outer side of the pressure chamber; and   a drive controller configured to output an auxiliary pulse which generates a volume change in the pressure chamber that is smaller than a volume change of the pressure chamber generated by an ejection pulse for ejecting ink from the pressure chamber to the first electrode, the second electrode, and the third electrode.   
     
     
         2 . The inkjet head according to  claim 1 , wherein
 the drive controller applies a first drive voltage to the first electrode and the second electrode, and outputs a second drive voltage obtained by reversing the first drive voltage to the third electrode as the auxiliary pulse.   
     
     
         3 . The inkjet head according to  claim 1 , wherein
 the drive controller applies a drive voltage to the first electrode and the third electrode, and sets the second electrode to a GND as the auxiliary pulse.   
     
     
         4 . The inkjet head according to  claim 1 , wherein
 the drive controller applies a drive voltage to the first electrode and the second electrode and sets the third electrode to a GND.   
     
     
         5 . The inkjet head according to  claim 1 , wherein
 the drive controller sets the first electrode and the second electrode as a GND and applies a drive voltage to the third electrode as the auxiliary pulse.   
     
     
         6 . The inkjet head according to  claim 1 , wherein the first actuator and the second actuator comprise a piezoelectric element. 
     
     
         7 . The inkjet head according to  claim 1 , wherein the drive controller is configured to output an auxiliary pulse which generates a volume change in the pressure chamber that is 50% or more smaller than a volume change of the pressure chamber generated by an ejection pulse for ejecting ink from the pressure chamber. 
     
     
         8 . An inkjet printer, comprising:
 a conveyance section configured to convey a medium; and   an inkjet head, the inkjet head comprising:
 a first actuator and a second actuator configured to constitute a pressure chamber; 
 a first electrode configured to contact the first actuator from an outer side of the pressure chamber; 
 a second electrode configured to contact the first actuator and the second actuator from an inner side of the pressure chamber; 
 a third electrode configured to contact the second actuator from the outer side of the pressure chamber; and 
 a drive controller configured to output an auxiliary pulse which generates a volume change in the pressure chamber that is smaller than a volume change of the pressure chamber generated by an ejection pulse for ejecting ink from the pressure chamber to the first electrode, the second electrode, and the third electrode. 
   
     
     
         9 . The inkjet printer according to  claim 8 , wherein
 the drive controller applies a first drive voltage to the first electrode and the second electrode, and outputs a second drive voltage obtained by reversing the first drive voltage to the third electrode as the auxiliary pulse.   
     
     
         10 . The inkjet printer according to  claim 8 , wherein
 the drive controller applies a drive voltage to the first electrode and the third electrode, and sets the second electrode to a GND as the auxiliary pulse.   
     
     
         11 . The inkjet printer according to  claim 8 , wherein
 the drive controller applies a drive voltage to the first electrode and the second electrode, and sets the third electrode to a GND.   
     
     
         12 . The inkjet printer according to  claim 8 , wherein
 the drive controller sets the first electrode and the second electrode as a GND, and applies a drive voltage to the third electrode as the auxiliary pulse.   
     
     
         13 . The inkjet printer according to  claim 8 , wherein the first actuator and the second actuator comprise a piezoelectric element. 
     
     
         14 . The inkjet printer according to  claim 8 , wherein the drive controller is configured to output an auxiliary pulse which generates a volume change in the pressure chamber that is 50% or more smaller than a volume change of the pressure chamber generated by an ejection pulse for ejecting ink from the pressure chamber. 
     
     
         15 . An inkjet printing method, comprising:
 contacting a first actuator from an outer side of a pressure chamber;   contacting the first actuator and a second actuator from an inner side of the pressure chamber;   contacting the second actuator from the outer side of the pressure chamber; and   outputting an auxiliary pulse which generates a volume change in the pressure chamber that is smaller than a volume change of the pressure chamber generated by an ejection pulse for ejecting ink from the pressure chamber to a first electrode, a second electrode, and a third electrode.   
     
     
         16 . The inkjet printing method according to  claim 15 , wherein
 outputting comprises applying a first drive voltage to the first electrode and the second electrode, and outputting a second drive voltage obtained by reversing the first drive voltage to the third electrode as the auxiliary pulse.   
     
     
         17 . The inkjet printing method according to  claim 15 , wherein
 outputting comprises applying a drive voltage to the first electrode and the third electrode, and setting the second electrode to a GND as the auxiliary pulse.   
     
     
         18 . The inkjet printing method according to  claim 15 , wherein
 outputting comprises applying a drive voltage to the first electrode and the second electrode, and setting the third electrode to a GND.   
     
     
         19 . The inkjet printing method according to  claim 15 , wherein
 outputting comprises setting the first electrode and the second electrode as a GND, and applying a drive voltage to the third electrode as the auxiliary pulse.   
     
     
         20 . The inkjet printing method according to  claim 15 , wherein
 outputting comprises outputting an auxiliary pulse which generates a volume change in the pressure chamber that is 50% or more smaller than a volume change of the pressure chamber generated by an ejection pulse for ejecting ink from the pressure chamber.